نتایج جستجو برای: شاخص dev ndvi

تعداد نتایج: 82546  

2009
Martha K. Raynolds Donald A. Walker

An understanding of the factors controlling the distribution of arctic vegetation will allow better prediction of the effects of climate change. This study examines the effect of the age of landscapes on the distribution of arctic vegetation. We compared time since deglaciation with the distribution of vegetation types and Advanced Very High Resolution Radiometer (AVHRR) satellite measures of g...

2009
Yu-Pin Lin Hone-Jay Chu Cheng-Long Wang Hsiao-Hsuan Yu Yung-Chieh Wang

This study applies variogram analyses of normalized difference vegetation index (NDVI) images derived from SPOT HRV images obtained before and after the ChiChi earthquake in the Chenyulan watershed, Taiwan, as well as images after four large typhoons, to delineate the spatial patterns, spatial structures and spatial variability of landscapes caused by these large disturbances. The conditional L...

2008
Boniface Oluoch Oindo

Spatial variability in species richness has been postulated to depend upon environmental factors such as climatic variability, Net primary productivity and habitat heterogeneity. The Advanced Very High Resolution Radiometer (AVHRR)-Normalized Difference Vegetation Index (NDVI) has been shown to be correlated with climatic variability, Net primary productivity and habitat heterogeneity. Moreover...

Journal: :Remote Sensing 2016
Christopher E. Soulard Christine M. Albano Miguel L. Villarreal Jessica J. Walker

To assess how montane meadow vegetation recovered after a wildfire that occurred in Yosemite National Park, CA in 1996, Google Earth Engine image processing was applied to leverage the entire Landsat Thematic Mapper archive from 1985 to 2012. Vegetation greenness (normalized difference vegetation index (NDVI)) was summarized every 16 days across the 28-year Landsat time series for 26 meadows. D...

2006
M. K. Raynolds D. A. Walker H. A. Maier

The Circumpolar Arctic Vegetation Map (CAVM) was used to analyze the distribution of NDVI and phytomass in the Arctic, providing data for understanding arctic vegetation patterns, assessing change, and calibrating models. The dominant trend in the analysis of Normalized Difference Vegetation Index (NDVI) was a decrease from south to north, correlating with bioclimate subzones and vegetation uni...

2011
Heng Duan

Based on a long-term vegetation index dataset of NDVI and meteorological data from 68 meteorological stations in the Qinghai-Tibet plateau and their relations with major climate factors were analyzed. The results show the following: 1) The linear trends of temperature in the Qinghai-Tibet plateau indicate that the temperature in the plateau generally increased, but it rose faster in the last 20...

Journal: :ISPRS Int. J. Geo-Information 2016
Pengyu Hao Li Wang Yulin Zhan Zheng Niu

Most methods used for crop classification rely on the ground-reference data of the same year, which leads to considerable financial and labor cost. In this study, we presented a method that can avoid the requirements of a large number of ground-reference data in the classification year. Firstly, we extracted the Normalized Difference Vegetation Index (NDVI) time series profiles of the dominant ...

ژورنال: فیزیک زمین و فضا 2018

در سال­های اخیر خشک­سالی تأثیر مخربی در بیشتر بخش­های اکولوژی، مدیریت منابع آب، و فرآیند­های زیست­محیطی برجا گذاشته است. در این تحقیق جهت ارزیابی خشک­سالی از اطلاعات حاصله از تصاویر سنجندهMODIS  در استخراج شاخص NDVI و DVI استفاده شده ­است. هدف از این تحقیق بررسی خشک­سالی­های هواشناسی در منطقه با استفاده از دو شاخص هواشناسی SPI و ZSI به‌صورت دوره­های ماهانه و همچنین بررسی رابطه بین شاخص پوشش گیا...

ژورنال: انسان و محیط زیست 2015

ارزیابی میزان تاج پوشش گیاهی، وضعیت و گرایش مراتع با توجه به نقش مراتع در حفاظت آب و خاک، اهمیت بسزایی دارد. پژوهش حاضر، با هدف تیپ‏بندی و ارزیابی اراضی مرتعی و تعیین درصد پوشش گیاهی  با استفاده از سامانه اطلاعات جغرافیایی (GIS) و شاخص پوشش گیاهی (NDVI) در بخشی از حوزه آبخیز حبله رود انجام شد. بدین منظور، تیپ بندی پوشش گیاهی با پیمایش عرصه‏های مرتعی، به روش فیزیونومیک- فلورستیک با نمونه برداری ...

2017
Aznam Yacoub Maâmar El-Amine Hamri Claudia S. Frydman

The DEv-PROMELA formalism is a new formalism that allows combining formal verification and discrete event simulation. In this paper, we propose to use a hierarchy of simulation formalisms to restrict the DEvPROMELA language. From sequential machine to the most expressive DEv-PROMELA formalism, this hierarchy helps designers to design models and to analyze systems in a progressive manner.

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